vlib/v/checker/tests/generic_sumtype_invalid_variant.vv:5:10: error: `MultiGeneric[bool, int, string]` has no variant `u64`
    3 | fn main() {
    4 |     mut m := MultiGeneric[bool, int, string](true)
    5 |     if m is u64 {
      |             ~~~
    6 |         println('hi')
    7 |     }
vlib/v/checker/tests/generic_sumtype_invalid_variant.vv:8:10: error: `MultiGeneric[bool, int, string]` has no variant `X`
    6 |         println('hi')
    7 |     }
    8 |     if m is X {
      |             ^
    9 |         println('hi again')
   10 |     }
